Flow control valve



June 16, 1953 H. KlRKi-IAM 2,642,088

FLOW CONTROL VALVE Original F 'iled April 17, 1944 3 Sheets-Sheet 1 Nil10 Aillll ,7" i 35; v v

June 16, 1953 KIRKHAM 2,642,088

FLOW CONTROL VALVE I Original .Filed April 1'7, 1944 3 Sheets-Sheet 2 igwuwwkw HJ SLL KIRKHQZ June 16, 1953 H. KIRKHAM FLOW CONTROL VALVE 3Sheets- Sheet 5 Original Filed April 1'7, 1944 v Patented June 16, 1953FLQW CONTROL, VALVE Hall 'Kirkham,

Cleveland, Ohio, assignor, by

mesne assignments, to The New York Air Brake Company, New York, N. Y., acorporation of New Jersey Original application April 17, 19,44, SerialNo. 662,839. Divided: and this application ()ictober 13, 1948, SerialNo. 54,279

This invention relates to control valves for hydraulic devices, and moreparticularly to such valves for handling the flow of liquid to and fromthe operating plungers of double acting rams associated with suchdevices asbulldozers, bull graders, scrapers, lift of a like nature.

More particularly the invention is concerned with a control valve to beintroduced between a doubleacting hoist or ram and a source of highpressure liquid for controlling the operation of the hoist or ram,permitting 'it to be raised or lowered; at anydesired speed andindependent of the load thereon.

' An important object of the invention includes the provision of acontrol valve for hydraulic devices having associated therewith flowcontrol valve means arranged to' control the return of liquidfrom thelow pressure side of the ram or hoist to thereservoir ata speed,dependent on the rate of supply offhigh pressure liquid, to the other,side of thehoist and wholly. independent of; load n the hoist which maytend to advance itfmore rapidly than the supply of high pressurefluid'.

One of theimportant features of the inventionlcomprises. the arrangementofjthe flow control valve wherein, its operation is transferred from oneside. of the hoist to, the other automatically by manual operation. ofthe main, control valve plunger.

Another mportant, feature of; the invention comprises the unique.arrangement. oi the, flow control. valve, whereby the return. of. lowpres.-

sure. iiquidiromjone side, ofthe hoistv or. ram

is. definitely controlled, by the. pressure on the operating liquid onthe other sidoQf the. ram,, Still another important. feature of theinventionresides in the, construction and arrangement of, the fiowcontrol valve whereby it is given a dashpotaction to prevent flutteringandsurging. For a more complete understanding of the inventionireferenceshould be had to thejaccompanyine' drawings and iollowing sp ificati n.wherein is discloseda single exemplary embodiment. of. the invention...with the understanding thatsu h. n s. and, modifications. may be. madetherein as fall; within the. scope. of; the. ap pendedclaims withoutdeparting fromotheispirit of, the invention.

Insaid drawings;

Figilis a sideelevation of, the assembled valve;

Fig, 2' is avertibal, central section through the same. on the. axis.ofthe. plungeri, Fig. 3 is a horizontal section through the cap trucksand machines.

' threaded passages 2 or cover element taken on broken line 3-3 of Fig.2 and illustrating both the system relief valve and the flow controlvalve;

Fig. 4 is a horizontal semi-section taken on line 4-4 of Fig. 2, notebeing made that the valve housing is symmetrical about the central line;

Fig. 5 is a horizontal section on line 5-5 of the base portion of thevalve illustrating the-high pressure inlet and check valve; and

Fig. 6 is a fragmentary horizontal section on line 6-6 of Fig. 1.

In the operation of various types of equipment by means of hydraulichoists or rams of the double acting variety, difficulty is sometimesexperienced by the load taking control of 'the'rate ofmovement thereofand causing the ram piston to" advance more rapidly than high pressurefluid is supplied: thereto, it being remembered that the fluidcan eitherbe throttled to limit the desired rateof movement or is obtained from apump of limited capacity. In the operation of earth moving equipmentsuch as bulldozers, bull graders, scrapers and the like. extremelysmooth lowering of the blade is desired to obtain the fine results ofwhich these machines are capable. Such lowering requires positivecontrol of the flowof low pressure liquid from the side of the piston ofthe ram opposite to that to,

which the high pressure liquid is delivered, so that the conditionnoted' above cannot exist; The present invention contemplates a uniquearrangement of the manually manipulatable controlvalve andthe flowcontrol valve.

Referring now to the drawings, and particu larly to Figs. 1, 2' and 5,it will be noted that the valve housing comprises three main parts,including lower or base section B, which is conveniently equipped withextending flanges l0, perforated as shown at H in Fig. 5 for mountingthe valve housing on any convenient support. As also seen in both Figs.1 and 5, the lower section provides threaded inlet passages l2, I2, sothat liquid from the pump may be delivered to either of these as is mostconvenient, a plugsuch as shown in the passage 12 in Fig.5 closing theunused one. I 1 The'central or control valve section C contains portsand passages for cooperation with the cap and bottom sections and withthe valve plunger P. It also contains, as" seen in Fig 4, Hi and I5,respectively, open through the side for conducting liquid to and fromthe two ends of the hoist or'ram. Since the section shown in Fig. 4 1ssymmetrical about the center line these passages I4 and I5 areduplicated on the other side, for the reasons pointed out in connectionwith the bottom section, and the ones not desired to be used can beappropriately plugged.

The top or cap section D includes through its upper surface the lowpressure fluid delivery passage I8 from which a pipe connects to asuitable reservoir or tank for the reserve liquid. This section alsohouses, as seen in Fig. 3, the system relief valve 29 and the flowcontrol valve 2| appropriately connected by passages to the centersection.

As shown in Fig. 2, the several sections of the valve housing meet alongplane surfaces 24 and 25, each intersected by the desired passages andports. Leakage is prevented by means of a gasket surrounding allpassages or ports or by means of composition rings, set in appropriategrooves such as are shown at 25 in Fig. 2. It will be understood thateach of the grooves or channels 26 is a continuous closed passage aroundits corresponding port. The rings may be of the swellant variety, whichexpand upon contact with the liquid to thereby effect a seal, thenon-swellant variety, which seal by deformation or they may be of acombination variety, which combines the virtues of the other two. Thesealing ring means of preventing leakage is considered superior to thegasket means. The several sections of the valve housing areappropriately secured together by through bolts, as shown at 21 in Fig.1.

In Fig. 5, bottom section B is shown as provided with a high pressureliquid chamber 28, to

which liquid is delivered from the constantly op erating pump of thepositive displacement type through one of the passages I2, I2. A coredpassage 29 leads from the chamber 28 to the check valve 30, comprisingahollow plunger 3| seating on the lip 32 of bore 33 extending frompassage 29. This plunger is seated by means of the housed spring 34abutting and positioned by screw cap 35. Oil under pressure is able tolift the plunger and to flow into passage 36 parallel to passage 29 andleading to vertical ducts 31 and 38, also seen in Fig. 2, This latterfigure also shows a vertical duct 39 leading from chamber 28. Each ofthe ducts 31, 38 and 39, extends through the top wall of the bottomsection and connects to a corresponding duct 31, 38' and 39',respectively, in the center section.

This center section is longitudinally bored as at 40 throughout itslength to provide a close working lit for the manually operablecylindrical plunger P, shown in this figure in its center or neutralposition. The bore 40 is variously intersected by channels, passages andports under the control of the valve plunger, which is equipped withsections of reduced diameter, or grooves, as shown, permitting fluidflow, when they are appropriately positioned between selected ones ofthe passages, channels and ports, as will later appear. The end portionsof the plunger extend out through the Walls Of the housing and aremaintained fiuid tight by appropriate seals 42 held in position by coverplates. These seals are vented by passages 43 which lead to the lowpressure discharge passage I8, as shown, to insure that the seals willnever be required to prevent leakage of high pressure fluid which mayseep by the controlling diameters of the valve plunger.

Passage 39 in the center section is continued in an offset passage 45which intersects the plunger bore. Closely adjacent it is the passage 46connected to low pressure exhaust chamber I8 by an extension 46'. valveplunger insures flow from 28 to 39 to 39 to 45 to 46 to 46' to I8 andback to the tank. This arrangement insures that the pump works againstsubstantially zero pressure when the valve plunger is in the neutralposition and no work is being done by the system. When the plunger ismoved toward the left, flow is stopped between 45 and 46 by the endsection 50 of the plunger and when it is moved to the right, by thenarrow land 5I.

When the plunger is in the neutral position shown, relief of the highpressure liquid as just described permits the check valve 30 to remainclosed, but if the plunger is moved in either di rection to close offthe flow between 45 and 46 a simultaneous connecting of one or the otherof the ram ports I4 and I5 with the high pressure liquid is effected asfollows: These ram ports have connected passage of corresponding numbersprimed which intersect the plunger bore as seen at I4 and I5 in Fig. 2and which are normally closed by the lands 53 and 54 of the plunger whenin neutral position. If this plunger is moved toward the left, passage38 is connected by groove 55 with passage I4, the check valve is openedand high pressure fluid flows to one side of the ram. At the same timeland 54 uncovers passage I5 and groove 56 in the plunger connects I5 topassage 60 which leads to passage 6I in the upper section of the valve.This passage extends up and around the hollow section 62 of the flowcontrol valve, and when this valve is lifted liquid flows from 6| intocross passage 54 which connects with 46' and the low pressure chamberI8, as clearly seen in Fig. 3. The operation just described results inmovement Of the ram in one direction under the action of high pressureliquid and causes the return of liquid from the opposite side of itspiston back to the tank under the control of valve 2 I.

Movement of the plunger P to the right reverses the operation of the ramas follows: High pressure liquid flows through the check valve 30 intopassages 31 and 31, through groove 66 in the plunger to the passage I5and direct to the other side of the ram. Low pressure fluid from theopposite face of the ram piston enters the valve at I4, flows into I4,and by means of groove 56 in the plunger enters 60 and BI and eventuallyfinds its way in the cross passage 64 and back to low pressure I8 asalready described. The check valve provides a safety means to hold theram in whatever position it may be and in spite of whatever load may beon it in the event of failure of the pump or the pipe line between thepump and the valve.

It will be noted that the high pressure chamber 38 is connected topassage 38 which intersects the plunger bore and this passage continues,having eventual connection to chamber 58 in the cover section of thevalve, which has a vertical extension 68', seen in Figs. 2 and 3. Thisis connected to bore I0 of the system relief valve. This bore isprovided with a pressed-in seat II against which the plunger 20 is heldby helical spring 72 under the control of adjustable follower I3positioned by means of screw threaded rod 14 in the cap I5; If for anyreason pump pressure becomes too great, such as by failure of the ram tomove, clogging of pipes or hoses, etc., unseating of the relief valve2!! permits discharge of high pressure liquid from 68 into 64 and henceto the tank. It will be noted that this relief is The groove 48 in theing the same.

available"at all'times when'the plungeris notin 38,38 is connected 7 theneutral position since to 28 whenever the check valve is lifted.

The flow control valve2'! which determines the :rate at which lowpressure fluid returns from the idling side of the ramplunger-tothereservoir by way of passages 60 and 6! is shownin Fig. 3.The valve plunger operates in .a bore 11 extending through the capsection of the housing transverse to cross passage 34 and-intersect- The'valveis of the spool type, having the solid end 18,the intermediateneck section and the upper section '52 hollowed out to receive the lighthelical .against the closure cap 8!). and tendingto press the valve withits end 18 against the adjustable stop 8| threaded into the cap 82 inthe opposite end of the bore. .This capiis bored with a larger diameterthan l! to permit liquid to flow from chamber 34 to the under face ofthe portion 13 to move the valve against the spring. As the valveplunger 2! is moved against the spring -more and more flow is permittedfrom 3'5! into '64. The cylindrical portion 62' of the plunger, whichnormally closes the passage ti, :down to 85 but is equipped with taperedslots :86 which are so arranged that complete closure between 6! and Mcan never be efiected. The tapering arrangement :of'these groovesinsures increased flow as the valve movesagainst the spring.

The chamber receiving spring is is extended in a small bore .83connected by a drilled hole 85 :tothe'outside of the narrow portionofthe valve 'plunger'to insure discharge :of any oil which may seepintothe spring chamber and also to impart "a dash pot action, to preventfluttering or rapid fluctuations in the movementof the valve plunger ina manner Well recognized.

' The passage 84 surrounding the head. E8 of the 1 valve plunger 2! isconnected by extension .95

and passage with (38', which, it will be remembered, is always open bydevious passages to the high pressure chamber 28. the system using thecapacity, it will be appreciated that if because of a load on the ramtending to move it in the direction it is already being urged by fluiddeliv- I ered to one side of its piston, there is a tendency 'for'thepiston to move more rapidly thanifluid'is :provided behind it, then thepressure on the liquid-being delivered by the pump will immediatelyfall. Advantage is taken of @thisti-n the operation of the flow controlvalve, for when pump-pressure is reduced in passage 86 the spring flowcontrol-valve plunger against its stop 8! and fluid flow from the lowpressure side of thefram piston is throttled between 6! and 54, stoppingthe unwarranted increase in speed of the ram from the loadthereon. Assoon as the pump catches up, pressure increases, fluid is delivered into84 and the valve isopened to the desired degree to permit the ram tooperate in its normal manner. To insure against rapid changes inpressure in M, the connection'between extension 90 and passage ti, bestshown in Fig. 6, is by wayof a restricted bore 93 controlled by anadjustable needle valve 9 as shown.

The needle valve 94 is in the nature of a metering pin which makes itpossible to controlaccurately the rate of flow of fluid from the lowpressure side of a double acting ram to prevent the piston from gettingahead of the fluid on the other side. Such controlled action makes itpossible to have any desired lowering speeds on such spring 59 abuttingextends I Since the pumpfor present valve is of a limited i 9 closes thezaeraoss instance, of a bulldozer -caused by the work. two ends of theram cylinderare different because position of said plunger which'rdoesnot allow for i machines. Theposition of the set screw 8| governs theamount of initial opening between pasalso governs the amount'of sages 6iand E i and travel of the flow control valve necessary. to bring themain recess in'this valve into play to fully open the passage from-ii!to 64.

In addition to the neutral and two power positions of the plunger'P, itmaybe pulled out an extreme distance to the right to provide whatisknown as, a float position. This movement carries land 5! into passageas so that high pressure fluid flows freely from into is and the pump isunloaded. Groove now connects rampart IE to passage til, which is alsoconnected to ram port !4' by groove 53. This provides for communicationbetween the liquid on the two sides of the piston of the ram, permittingthe blade, for to assume any position The displacement of the of thepresence of the piston rod at one end,-.so that when moving in onedirection an excess of oil must be discharged and when moving in theother direction oil must be added to the circuit. This is simplyeffected in the valve shown, since thepassage til to which both ends ofthe ram cylinder are now connected is always uninterrupted incommunication with low pressure cross passage Gil because the valve '2!is never permitted to fullyclose'communication between 6'! and 64because of the grooves 86. In this way oil from the reservoir can bedelivered to the ram circuit or can be discharged from the latter to thereservoir to provide forthe floating action. If for any reason the floatposition of the valve is not required, then the construction of valve2ijis modified by the omission of the groovesfit, which allow constantcommunication between ii! and 64 and thus prevent destructive loadimposed pressures occurring inpassages'tli and t I These pressures canonly occur when plunger P is in the floatposition since this is the onlyoperating pump induced high pressure fluid acting on end .1801 plunger2-! to thus move it against spring -19 to bring passages 5! and 64 intocommunication via the central groove of plunger 2L. Itis thus evidentthat elimination of the float condition automatically removes any needfor grooves .86 and thus allow for simplification of plunger. 2

Because of the peculiar arrangement of .the passages and ports in theintermediate section of the valve housing, more than one suchsection canbe arranged between the bottom and cover sections, permittingcontroloiseveral double actingrams. .In' order to insure properoperation with multiple pressure sections it will be noted that passage31 as well as passage, 38 extends vertically entirely section and isclosed 01? at 96 by a blank section of the cap or cover. The passage 66is also carried through to be closed off by the bottom section, as shownat These extensions provide through passages in the eventof multiple useof plunger sections. tions are in use the ones above and/or below theone actually in operation, act merely as elongations of the passages orducts between the various oil channels in adjoining sections.

This application is a division of my copending application Serial No.662,839, filed April 17, 1944, and issued July 22, 1952, as Patent2,604,327, for Control Valve With Flow Control.

I claim:

1. A flow control valve of the type described,

through the central housing Where several of these seccomprising ahousing having a bore; means closing the ends of the bore; a ductintersecting said bore; a plunger having spaced lands and anintermediate groove movablein said bore between limits with said grooveand duct in communication; a passage intersecting said bore andsubstantially closed by one of said lands when the plunger is at one ofits limits; a spring to so position the valve plunger; means tointroduce high pressure liquid into said bore at the end opposite saidlast mentioned land to move the plunger against said spring and furtheropen said passage to said groove; and passage means in said plunger fromthe bore beyond the last mentioned land to said groove to afford adashpot action therefor.

2. A flow control Valve for limiting the rate of movement of a doubleacting hoist to that determined by the delivery capacity of the liquidpump therefor, comprising a housing having a bore closed at its ends; aduct intersecting said bore; a plunger freely reciprocable in said bore,having end lands with a, working fit therein and a groove arranged toregister at all times with said duct; a chamber at one end of said bore;a delivery bore for operating liquid, opening into said chamber; aspring biasing said plunger toward said chamber; an inlet passage forfluid intersecting said bore and substantially closed by the land at theopposite end of the bore from the said chamber when the plunger is atone of its limits of reciprocation, movement of the plunger against thespring providing progressively increasing communication between thepassage and duct; means to limit the movement of the plunger toward saidchamber always to maintain limited communication between the passage andduct; means to adjust the rate of flow in said delivery bore; and arestricted passage in said plunger from the end opposite said chamber tothe surface of said groove to provide dash-pot action.

3. A flow control valve for limiting the rate of movement of a doubleacting hoist to that determined by the delivery capacity of the liquidpump therefor, comprising a housing having a bore closed at its ends; aduct intersecting said bore; a plunger freely reciprocable in said bore,having end lands with a working fit therein and a groove arranged toregister at all times with said duct; a chamber at one end of said bore;a delivery bore for operating liquid, opening into said chamber; aspring biasing said plunger toward said chamber; an inlet passage forfluid intersecting said bore and substantially closed by the land at theopposite end of the bore from the said chamber when the plunger is atone ofits limits of reciprocation, movement of the plunger against saidspring providing progressively-increasing communication between thepassage and duct; means to limit the movement of the plunger toward saidchamber always to maintain limited-communication between the passage andduct; and adjustable means in said delivery bore to meter liquid movingin either direction therein.

4. A flow control valve for limiting the rate of movement of a doubleacting hoist to that determined by the delivery capacity of the liquidpump therefor, comprising a housing having a bore closed at its ends; aduct intersecting said bore; a plunger freely reciprocable in said bore,having end lands with a working fit therein and a groove arranged toregister at all times with said duct; a chamber at one end of said bore;a delivery bore for operating liquid, opening into said chamber; aspring biasing said plunger'tovvard said chamber; an inlet passage forfluid intersecting said bore and substantially closed by the land at theopposite end of the bore from the said chamber when the plunger is atone of its limits of reciprocation, movement of the plunger against thespring providing progressively increasing communication between thepassage and duct; means to limit the movement of the plunger toward saidchamber always to maintain limited communication between the passage andduct; a closed chamber at the opposite end of said bore; and arestricted passage connecting said last mentioned chamber to said duct.

5. The valve as claimed in claim 4 in which said limiting means for theplunger is adjustable and in which the land opposite the first mentionedchamber has a longitudinal slot of decreasing depth extending from thegroove toward and intersecting the passage at all times.

HALL KIRKHAM.

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